use any brand of modern oil with the exception of non detergent oil, and the oil that has the red circle on the front of the container that says for gasoline engines only, that oil is for modern engines with roller tappets and they do not need zink, Kevin in NJ is right, no need to change oil every 500 miles, that was back in the times when there were no paved roads and they drove there cars in extremely conditions, and the oil back then that it need to be changed that often, the non detergent oil used then is only use in air compressors now, and i wonder if it even should be used then, you guys are following a maintance guide that is 70 years old and pertains to the the available of lubricants availabe then, use the modern oils and change every 1500 miles or so, or not , depending on your preference